The yesod-auth-zendesk package

Note that this is an unusual yesod-auth-* package. We do not
define an AuthPlugin because the user can't log in to your
website via Zendesk (it's the opposite, they login in Zendesk
via your website). Instead, this plugin defines an Yesod
subsite that you may include on your site; the subsite defines
a route that accepts incoming users from Zendesk and
authenticates them.